In the field of communications, the need for high-speed transmission of data including video and audio has continued to increase. Moreover, in addition to the demand for higher bandwidth, there has also been an increased need for various types of services that employ different protocols. Further, customers of high-speed networks (e.g., companies providing different networking services) may desire to transport data employing packet-based data streams. Examples of the types of packets that can be placed into such data streams include Asynchronous Transfer Mode (“ATM”), Internet Protocol (“IP”), Frame Relay, Voice Over IP, and Point-to-Point Protocol (“PPP”).
Different network elements can be employed in various network configurations to allow for transmission of these packets. One type of network element is a bridge as defined by the IEEE 802.1 standard. Bridges can be employed to interconnect local area networks (LANs). In contrast to routers, bridges are independent of a given protocol. Accordingly, a bridge acts as a forwarding mechanism without analyzing and routing based on protocols of the given packets.
One type of bridge is the learning bridge, which examines the source address within packets being received on a port and generates and updates its internal tables to associate the port with the given source address. Accordingly, if a packet having this address as its destination is received, the bridge can forward this packet to the associated port stored within its internal table. However, if a packet is received wherein the destination address is not included with the internal tables, the bridge floods the packet to the different ports associated with the spanning tree for this source port. Disadvantageously, this flooding of packets across different ports can overwhelm such ports and cause the loss of packets because the ports will not be able to process all of the incoming packets.
One conventional approach for a network element that includes a learning bridge is to include a common database stored in a control card, which is shared across a number of line cards within the network element. Accordingly, when a line card receives packets wherein the common database needs to be updated, the line card communicates this information to the control, which updates the common database. Disadvantageously, the control card is required to be executing at least as fast as:2*the line rate*the number of line cards  (1)in order to handle the updates to the common database when the line cards are receiving and transmitting at an optimal rate and thereby preclude the flooding of packets across the different ports of the line cards.
Another typical approach for a network element that includes a learning bridge is to include a database on each line card, that is shared by the ingress and egress portions of the line card. However, the logic that is updating this database on the line card is required to be executing at least as fast as:2*the line rate  (2)in order to handle the updates to this database when the line card is receiving and transmitting at an optimal rate and thereby preclude the flooding of packets across the different ports of the line cards.